Tilt compensation linkage for tilting bulldozer moldboard

ABSTRACT

Compensating linkage for a tilting bulldozer moldboard including a link depending from the rear of the moldboard with its lower end pivotally connected, at longitudinally spaced points, to the two dozer push arms.

United States Patent Rockwell et al.

[451 Apr. 4, 1972 [54] TILT COMPENSATION LINKAGE FOR TILTING BULLDOZERMOLDBOARD [72] Inventors: Harvey W. Rockwell; Wesley A. Poore,

both of Springfield, Ill.

[73] Assignee: Allis-Chalmers Manufacturing Company,

Milwaukee, Wis.

[22] Filed: June 1, 1970 [21] Appl. No.: 41,899

[52] U.S. Cl ..l72/803, 172/806 [51] Int. Cl. ..E02f 3/76 [58] Field ofSearch ..172/803, 804, 801 807, 806

[56] References Cited UNITED STATES PATENTS 3,395,764 8/1968 Wirt..l72/803 3,503,457 3/1970 Smith et al 172/803 3,049,820 8/1962 Lichti 172/803 3,025,620 3/1962 Liess 172/803 FOREIGN PATENTS OR APPLlCATlONS1,136,998 12/1968 Great Britain 172/803 Primary Examiner-Robert E.Pulfrey Assistant Examiner-Stephen C. Pellegrino Attorney-Charles L.Schwab, Robert B. Benson and Kenneth C. McKivett [5 7] ABSTRACTCompensating linkage for a tilting bulldozer moldboard including a linkdepending from the rear of the moldboard with its lower end pivotallyconnected, at longitudinally spaced points, to the two dozer push arms.

7 Claims, 4 Drawing Figures Patnted April 4, 1972 3,653,450

2 Sheets-Sheet l Patented April 4, 1972 2 Sheets-Sheet 2 i www wwgz M m2 m um WWW TILT COMPENSATION LINKAGE FOR TILTING BULLDOZER MOLDBOARDThis invention relates to an improved compensating mechanism for a tiltdozer and particularly to the provision of a link depending from therear of the blade and forming a longitudinal link between the diagonalbrace structures of the push arms.

I'leretofore others have proposed compensating mechanisms for tiltdozers, such as shown in U.S. Pat. Nos. 3,049,820, 3,049,821 and3,395,764. Such designs have not proven entirely satisfactory from thestandpoint of cost, function and service.

It is an object of the present invention to provide an improved dozertilt compensating mechanism which is simple in design, is low in costand gives long trouble-free service.

It is a further object of this invention to provide a dozer tiltcompensating mechanism wherein the diagonal brace structures of the pusharms are interconnected by a longitudinally disposed link.

It is a further object of this invention to provide a dozer tiltcompensation linkage of the type described in the previous objectwherein the longitudinally disposed link depends from a pivot connectionwith the rear of the moldboard.

Theseand other objects and advantages of the present invention will beapparent when the following description is read in conjunction with thedrawings, in which:

FIG. 1 is a partial side view of a tractor with a tilt dozer in whichthe present invention is incorporated;

FIG. 2 is a top view of the tractor and dozer of FIG. 1;

FIG. 3 is a section view taken on the line III-III in FIG. 2; and

FIG. 4 is a section view taken on the line IVIV in FIG. 3.

Referring to FIGS. 1 and 2, the push arms 11, 12 of the bulldozer 13 areconnected on a transverse axis 14 to the track frames of a crawlertractor 16 by ball and socket joints l7, 18. The front end of the pusharms are connected to transversely spaced points of the lower rear ofthe dozer moldboard 21 by spherical pivot connections 22, 23. Tilting ofthe moldboard is controlled by an extensible and contractible tilt bracein the form of a double-acting hydraulic jack 26, the rod 27 of which ispivotally connected to the upper rear of the moldboard by ball andsocket connection 28 and the cylinder 29 of which is pivotally connectedto push arm 11 and pin 31. At the opposite lateral side of the dozer 13,an upwardly extending tilt brace 32 has its opposite ends pivotallyconnected to the push arm 12 and upper rear of the moldboard 21.

The dozer is raised and lowered, about transverse axis 14, bycontraction and expansion of a pair of double-acting jacks 33, 34 havingtheir rods 36, 37 pivotally connected to brackets at the rear of themoldboard 21 and their cylinders 38, 39

pivotally connected to the tractor 16. As customary, the hydrauliccontrol for the jacks 33, 34 includes means (not shown) forhydraulically interconnecting corresponding ends of the cylinders 38,39.

The push arms include diagonal brace structures in the form of inwardlyextending legs 41, 42. In order to interconnect the inner ends of theselegs 41, 42 to provide lateral rigidity to the dozer and still allowrelative longitudinal movement between the moldboard and the free endsof legs 41, 42, there is provided a longitudinal link 46 pivotallyconnected at longitudinally spaced points to the ends of legs 41, 42.The details of the link 46 and its connections to the legs 41, 42 andmoldboard 21 are shown in FIGS. 3 and 4. The legs 41, 42 of the pusharms are universally connected to the link 46 by universal pivots in theform of spherical bearing assemblies 47, 48 which are' identical inconstruction and lie in the longitudinal vertical plane of the dozer andtractor. As shown in FIG. 4, bearing assembly 48 includes a pin 49 onwhich a spherical bearing 51 is held by a cap 52 and a bushing 53 withspherical socket which is held in place in bore 54 of link 46 by a pairof snap rings 56, 57. The upper end of the longitudinal link 46 isuniversally connected to brackets 58, 59 of the moldboard 21, forlongitudinal fore and aft swinging movement, by a spherical bearingassembly 61 including engaging spherically surfaced bearing parts 62,63. The center of the upper pivot connection of assembly 61 is spaced adistance 2 vertically above a line f passing through the centers oflower universal pivot connections of assemblies 47, 48 which is slightlygreater than twice the distance g between the centers of the universalpivot assemblies 47 and 48. This properly allows the longitudinalmovement of link 46 without adversely affecting the vertical position ofthe free ends of legs 41, 42.

OPERATION When the tilt brace jack 26 is expanded, the lateral end ofthe moldboard 21 to which the jack is connected will rise relative toits other lateral end. This will cause the free ends of legs 41, 42 tomove closer to the rear of the moldboard. Depending link 46 permits thiswhile still providing a connection between the push arms ll, 12 toprovide lateral stability for the mold board. By pivotally connectingthe link 46 to the rear of the moldboard the free ends of the legs 41,42 are supported in the desired vertical position so they perform thedesired diagonal bracing function. If the tilt jack 26 is contracted theadjacent moldboard end will be lowered and once again the ends of legs41, 42 will move closer to the moldboard 21. Thus the depending andlongitudinally extending link 46 and the longitudinally spaced pivotconnections 47, 48 with the push arms 1 l, 12 serve to compensate fordimensional changes occurring during tilting of the dozer.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination with a dozer having. a pair of longitudinallyextending and laterally spaced push arms pivotally connected at theirfront ends to the rear of a moldboard and a pair of tilt bracesextending upwardly between the top of the push arms and the blade, atleast one of the tilt braces being extensible, a tilt compensatingarrangement comprising:

a pair of diagonal brace structures extending laterally inwardly fromsaid push arms toward one another with their inner ends terminating inlongitudinally spaced relation to one another adjacent the rear of saidmoldboard,

a longitudinally extending link pivotally connected at longitudinallyspaced points to said inner ends, respectively, of said bracestructures, and

means pivotally connecting said link to the rear of said moldboard at apoint spaced vertically from said longitudinally spaced pointspermitting longitudinal fore and aft swinging movement of said link, thedistance between said point of pivot of said link to said moldboard anda line between the points of pivot between said link and structures isgreater than the distance between said points of pivot between said linkand structures.

2. The invention of claim 1 wherein said pivot connections between saidlink and said structures are universal pivot connections.

3. The invention of claim 2 wherein said pivot connection between saidlink and said moldboard is a universal pivot connection.

4. The structure of claim 3 wherein said universal connections arespherical bearing connections.

5. The structure of claim 1 wherein said diagonal brace structures arerigidly connected to said push arms.

6. In combination with a dozer having a pair of longitudinally extendingand laterally spaced push arms pivotally connected at their front endsto the rear of a moldboard and a pair of tilt braces extending upwardlybetween the top of the push arms and the blade, at least one of the tiltbraces being extensible, a tilt compensating arrangement comprising:

a pair of diagonal brace structures rigidly secured to and extendinglaterally inwardly from said push arms toward one another with theirinner ends terminating in longitudinally spaced relation to one anotheradjacent the rear of said moldboard,

dinally spaced points. 7. The invention of claim 6 wherein saidlongitudinally spaced points lie substantially in the longitudinalvertical plane ofsaid dozer.

1. In combination with a dozer having a pair of longitudinally extendingand laterally spaced push arms pivotally connected at their front endsto the rear of a moldboard and a pair of tilt braces extending upwardlybetween the top of the push arms and the blade, at least one of the tiltbraces being extensible, a tilt compensating arrangement comprising: apair of diagonal brace structures extending laterally inwardly from saidpush arms toward one another with their inner ends terminating inlongitudinally spaced relation to one another adjacent the rear of saidmoldboard, a longitudinally extending link pivotally connected atlongitudinally spaced points to said inner ends, respectively, of saidbrace structures, and means pivotally connecting said link to the rearof said moldboard at a point spaced vertically from said longitudinallyspaced points permitting longitudinal fore and aft swinging movement ofsaid link, the distance between said point of pivot of said link to saidmoldboard and a line between the points of pivot between said link andstructures is greater than the distance between said points of pivotbetween said link and structures.
 2. The invention of claim 1 whereinsaid pivot connections between said link and said structures areuniversal pivot connections.
 3. The invention of claim 2 wherein saidpivot Connection between said link and said moldboard is a universalpivot connection.
 4. The structure of claim 3 wherein said universalconnections are spherical bearing connections.
 5. The structure of claim1 wherein said diagonal brace structures are rigidly connected to saidpush arms.
 6. In combination with a dozer having a pair oflongitudinally extending and laterally spaced push arms pivotallyconnected at their front ends to the rear of a moldboard and a pair oftilt braces extending upwardly between the top of the push arms and theblade, at least one of the tilt braces being extensible, a tiltcompensating arrangement comprising: a pair of diagonal brace structuresrigidly secured to and extending laterally inwardly from said push armstoward one another with their inner ends terminating in longitudinallyspaced relation to one another adjacent the rear of said moldboard, alongitudinally extending link pivotally connected at longitudinallyspaced points to said inner ends, respectively, of said brace structuresfor universal movement relative thereto, and means universallyconnecting said link to the rear of said moldboard at a point spacedvertically from said longitudinally spaced points.
 7. The invention ofclaim 6 wherein said longitudinally spaced points lie substantially inthe longitudinal vertical plane of said dozer.